1. Field of the Invention
The present invention relates to a method for a personal paging in a telephone private branch exchange.
More specifically, the invention relates to such a method in which the private branch exchange has a central control device, a central memory, and a central personal paging device that respectively encompasses call apparatus allocated to the persons to be paged as needed, to which call apparatus, given an appropriately preselected operating mode of the personal paging device, the subscriber line number of the calling subscriber communicated from the central control of the personal paging device is transmitted in addition to a call signal, this being optically or acoustically transmitted by the call device and the line number of the calling subscriber is utilized by any arbitrary subscriber set of the telephone private branch exchange for connecting the calling subscriber to the call subscriber.
2. Description of the Prior Art
Within telephone private branch exchanges, personal paging devices offer the possibility of being able to reach specific subscribers at any time. To this end, these subscribers carry a portable call device. The presence of a call request is indicated to the subscriber with this device. The signalization can occur in various ways and with a variety of informational scope. In a simple operating mode of the personal paging device, the signaling occurs with a ringing tone or by lighting a signal lamp. What this means for the call subscriber is that he should seek out a subscriber set of the telephone private branch exchange as quickly as possible and that he must identify himself thereat on the basis of a previously-declared identifying number if the connection is to be completed. Dependent on the operating mode, he either receives information regarding who wishes to reach him or he is directly connected to the calling subscriber only on the basis of this report.
Another possibility of signaling offers an operating mode wherein the ringing tone, or the signal lamp, sounds or lights in combination with an optical display on a display device or, respectively, with an acoustical message via a loudspeaker, of the call device. The telephone number of the calling subscriber is already transmitted to the called subscriber via the display or, respectively, via the loudspeaker, at the time of signaling. The paging event is thereby separated from the reporting event. The call subscriber can therefore realize the desired connection at a time suitable for him. This operating mode is permanently set since the persons that have a calling device expect that they will also be informed of the telephone number of the calling subscriber via the display, or the loudspeaker, in the case of a personal call. A constant changing in the operating mode of the personal paging device, together with the change of the signaling scope involved therewith, would lead to confusion of the persons to be called. Such a change of the operating mode, however, would always be necessary when the telephone number of the calling subscriber needed for executing the page request given the preselected operating mode is not known to the telephone private branch exchange.
This telephone number is consistently not known when the call request comes from an external telephone exchange. This telephone exchange can be connected to the telephone private branch exchange via a tie trunk or inter-exchange link. Given such a call request, the telephone private branch exchange is informed of only the purpose of the switching event, but not of the subscriber line number of the calling subscriber. When the operating mode is not changed in such a case, then this leads to the situation that the personal page is not possible due to the lack of information. The calling subscriber is either routed to a manual switching position or he receives a busy signal.